All other email clients render the text, but not in Apple Mail 9 or 10. Images show, and all of the styling etc, but just no text.

I am using Open Sans via google fonts, as mentioned the font shows everywhere else (where its supported anyhow).

A question like this was posted 4 months ago (https://litmus.com/community/discussions/5585-custom-fonts-blank-on-ios-apple-mail-and-outlook-2016) but has no replies (apart from one that isnt helpful).

Is this an issue you are aware of, familar with, seen before?

Addtionally, if i remove the link to the web font, then text of course shows normally. Here is my link, nothing unusual:

<link rel="stylesheet" type="text/css" href='http://fonts.googleapis.com/css?family=Open+Sans:300,400,600,700,800'>